The Commons authorities will consider how to respond to a damning report which laid bare how a toxic culture in Parliament allowed bullying and harassment to thrive.

The scathing criticism in Dame Laura Cox’s report has heaped pressure on John Bercow, with critics claiming a change in culture can only begin with a new Commons speaker.

The House of Commons Commission will consider the Cox report at a meeting on Wednesday, with Mr Bercow stepping aside from his normal role as chairman of the panel which includes senior MPs and officials.

Dame Laura was appointed to head an investigation after BBC Two’s Newsnight highlighted claims of bullying of Commons staff by MPs and other staff, including Mr Bercow – allegations which he strongly denied.

Labour said the report “highlights a culture and practices that are unacceptable in any workplace” and accepted the recommendations.

The party called for changes to be made as quickly as possible, including an independent process for complaints against MPs which does not involve fellow MPs deciding on cases, and ensuring the new Independent Complaints and Grievance Scheme should also be open to historical allegations.

The party’s representatives on commission – Valerie Vaz and Dame Rosie Winterton – will call for the necessary changes to be “implemented as quickly as possible, working with trade unions and other stakeholders,” a Labour spokeswoman said.

The FDA union, which represents senior public servants, warned the commission against watering down the Cox report’s recommendations.

Assistant general secretary Amy Leversidge said: “Any delay in agreeing the recommendations in full will be seen by staff for what it is, a tactic to allow MPs to get away with implementing a watered-down version later. ”

The union warned that staff could be forced to go on strike unless there was a change of culture as their loyalty to Parliament “has been pushed to breaking point”.

Ms Leversidge said: “If the commission, after such a damning inquiry, votes for anything less than a full and immediate implementation of Dame Laura’s recommendations, staff will naturally ask themselves ‘if not now, when?’.

“If the House is still willing to continue to tolerate and conceal abuse, even after the searing criticism in Dame Laura’s inquiry, then the commission must be aware that they will be pushing staff to consider an unprecedented step as they will have little other choice to affect change.”

When the commission discusses the Cox report it will be chaired by independent external member Jane McCall, rather than the Speaker.

On the eve of the meeting, three Tory MPs quit a body Mr Bercow set up to improve “inclusion” at Westminster.

Will Quince, Mims Davies and Anne Milton resigned from the Commons Reference Group on Representation and Inclusion, which is chaired by Mr Bercow.

In a statement, Mr Quince said he did not believe Mr Bercow was the right person to resolve the “numerous and serious issues” which had been raised about the conduct of some MPs and Commons staff.

“In the light of the Dame Laura Cox report, sadly I cannot in good conscience remain as a member of the group while John Bercow is chair,” he said.

Conservative MP for Colchester Will Quince (PA)

In a statement, a spokeswoman for the Speaker’s Office said Mr Bercow had accepted their resignations “with regret” and paid tribute to them as “stellar members” of the group.

She said the Speaker would consider the group’s future after the House of Commons Commission meeting on Wednesday.

“Dame Laura Cox’s report has highlighted some of the most significant challenges women face in our parliamentary culture,” the spokeswoman said.

“In the spirit of an independent approach, the Speaker feels it is right to reflect on the best means of tackling these cultural issues via the House’s response to the Cox report.”